1. Field of the Invention
This invention relates to methods for manufacturing panels, as well as to panels which are obtained or can be obtained by means of such method.
More particularly, the invention relates to a method for manufacturing panels of the type comprising at least a substrate and a decor provided on this substrate. In particular, the invention relates to a method that involves printing at least a portion of the decor onto the substrate, whether or not by the intermediary of primer layers.
2. Related Art
As an alternative for the traditional laminated panels, wherein a pre-printed paper sheet is provided, for example, glued or pressed, on a substrate, and wherein the print of the paper sheet forms the decor of the panel concerned, panels, wherein a decor, whether or not directly, is printed on the substrate already are known, for example, from the patent documents U.S. Pat. No. 3,173,804, GB 2 324 982, WO 01/48333, WO 2004/042168, WO 2005/116361, WO 2006/002917 and EP 1 717 030.
Generally, a difference can be made between two techniques by which a decor can be printed on a substrate. On the one hand, as in U.S. Pat. No. 3,173,804, an analogous printing technique can be applied, such as offset printing, wherein a print is formed on a roll, for example, a rubber roll, and this print is transferred via the roll on the substrate, whether or not by means of primer layers, and on the other hand, as in WO 01/48333, a digital printing technique can be applied, such as a technique wherein printing heads form the print directly on the substrate, whether or not by the intermediary of primer layers. In this last case, use can be made, for example, of one or more inkjet printers.
Where in the traditional laminated panels mostly use is made of a transparent or translucent paper sheet extra provided with resin, such as an overlay, for protecting the decor against wear and/or scratches, in the aforementioned alternative panels mostly a wear-resistant layer of lacquer is provided on the printed decor. By means of a decor printed on the substrate and such wear-resistant layer of lacquer mostly more lively and/or color-proof decors are obtained in comparison with laminated panels, as the applied lacquer layer mostly has a better transparency than the protective top layers used in laminated panels.
Said wear-resistant lacquer selectively may render a glossy or matte effect, however, mostly keeps forming a flat top layer on the panel. The possibilities known from the state of the art for remedying this and forming in this lacquer layer impressions or other relief forms for imitating, for example, a wood structure or stone structure, up to now do not yet achieve the realism which at present in fact can be achieved in laminated panels. For examples of structures in laminated panels, reference is made to the patent documents WO 01/96688, WO 01/96689, WO 2006/063803, WO 2006/066776, US 2006/0144004 and WO 2007/072198.
A first prior art possibility for forming relief at the surface of a panel with a decor printed on the substrate consists of forming recesses in said wear-resistant lacquer layer. This can be performed, for example, by forming impressions in this layer by means of a press element or by the local application of chemicals dislodging the lacquer layer, as it is the case, for example, in U.S. Pat. No. 6,991,830. The known structures provided by means of this first possibility are limited in depth, as they, according to the state of the art, remain limited in the lacquer layer. Forming deep impressions directly in the lacquer layer holds certain risks. With large deformations, it is possible that the lacquer layer breaks or is interrupted.
A second prior art possibility for forming structure at the surface of a panel with a decor printed on the substrate is described, for example, in said WO 2004/042188. According to this second possibility, for example, the substrate can be provided with a structure or relief before the print is performed. The obtained structure remains present after printing the substrate and after providing the wear-resistant lacquer layer. Such technique allows obtaining deeper structures or deeper relief than this is the case with said first possibility. Introducing level differences on the substrate still to be printed, however, leads to increased complexity when performing the printing process. Thus, for example, it is possible that in case of digital printing, the focus distance and/or the position of the printer must be adjusted according to the structure of the substrate to be printed. In the case of offset print, it is possible that the roll providing the print on the substrate is not sufficiently flexible to follow the provided structure, with as a possible consequence the occurrence of undesired unprinted portions.